In commonly assigned U.S. Published Application 2006/0169941 (Ser. No. 11/343,105, filed Jan. 30, 2006), the disclosure of which is incorporated herein by reference, there is described a diaphragm-style valve in which the portion of the diaphragm which comes into sealing contact with the valve seat of the valve, or which is sealed to the valve body, is made softer than the remainder of the diaphragm or valve seat by coating with a polymer. Because of the relative softness of the polymer coating, a high integrity seal is more easily formed between these components because this coating deforms to accommodate minor voids, protrusions or other imperfections in the surfaces being sealed.
In accordance with this invention, a softer polymer coating is made from a self-assembled monolayer (“SAM”). The SAM soft polymer coating may be used in a wide variety of different applications where seals are made. These applications include, but are not limited to flow control devices, such as valves, and coupling devices, such as fittings. For example, in one embodiment the soft polymer coating of the diaphragm valve disclosed above is replaced with a SAM coating.
Thus, this invention in one embodiment provides a diaphragm style valve having a valve seat and a metal diaphragm structured to sealingly engage the valve seat at a sealing interface, wherein the portion of the diaphragm defining the sealing interface, or the portion of the valve seat defining the sealing interface, or both, carry a self-assembled monolayer.
In addition, this invention in another embodiment provides a flow control device comprising a body portion including a valve seat and a control member assembled with the body portion, the control member and/or the body portion being formed from a base material and a sealing surface, the sealing surface being configured for contacting and forming a sealing interface with the body portion, the valve seat or both, wherein the sealing surface is formed from a self-assembled monolayer.
Further, this invention in another embodiment provides a coupling device comprising a body portion and a seal member assembled with the body portion, the body portion and/or the seal member being formed from a base material and a sealing surface, the sealing surface is made from a self-assembled monolayer and more readily conforms to the mating surface to which it seals.